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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 343 records · Page 19

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NASA NTRS1982

A study of dirigibles for use in the Peruvian Selva Central Region

The potential for dirigibles as transports in the Selva Central region of Peru was evaluated by means of a mission and economic analysis. A total requirement to transport over 19 million tons (t) of agricultural produce, lumber, and meat was projected by the year 2004. A primary route involving zones for loading and delivering this cargo was identified. Although dirigibles are capable of short field operation, all existing airfields must be enlarged in width to allow for all conditions of wind and weather and to provide space for overnight mooring. A maintenance base and operations headquarters, complete with hangar and other service facilities would be required. The quantities of cargo to be carried establish requirements for fleets of dirigibles of various sizes and capacities. Cargo capacities of 5 to 100 tons were identified. Fleet sizes up to 106 dirigibles (in 20 t capacities) would be required. Dirigibles were assumed to be of the nonrigid type except in the 100 t category for which rigid characteristics were assumed. A method of determining dirigible costs was developed. The values derived were then applied to an economic analysis to determine initial investment and operating costs. It was found that larger dirigibles of approximately 20 t capacities or higher could offer significant cost benefits over airplanes, provided cruise speeds were higher than 100 km/hr.

Mayer, N. J.↗

NASA NTRS1984

Economic impact of fuel properties on turbine powered business aircraft

The principal objective was to estimate the economic impact on the turbine-powered business aviation fleet of potential changes in the composition and properties of aviation fuel. Secondary objectives include estimation of the sensitivity of costs to specific fuel properties, and an assessment of the directions in which further research should be directed. The study was based on the published characteristics of typical and specific modern aircraft in three classes; heavy jet, light jet, and turboprop. Missions of these aircraft were simulated by computer methods for each aircraft for several range and payload combinations, and assumed atmospheric temperatures ranging from nominal to extremely cold. Five fuels were selected for comparison with the reference fuel, nominal Jet A. An overview of the data, the mathematic models, the data reduction and analysis procedure, and the results of the study are given. The direct operating costs of the study fuels are compared with that of the reference fuel in the 1990 time-frame, and the anticipated fleet costs and fuel break-even costs are estimated.

Powell, F. D.↗

NASA NTRS1987

Insurance and indemnification implications of future space projects

NASA options regarding insurance and indemnification policies as they relate to NASA customers and contractors are described. The foundation for the discussion is the way in which NASA is planning to return the Space Shuttle fleet to safe flight as well as current U.S. policy concerning future uses of the Shuttle fleet. Issues discussed include: the nature of the Shuttle manifest; the policy regarding property damage or destruction; insurance against liability to third parties; the reduction of the scope of the risk to be insured; NASA as the insurer; a sharing arrangement between the user and NASA; and contractors and subcontractors involved in Shuttle operations.

O'Brien, John E.↗

NASA NTRS1987

Flight problem evaluation for Space Shuttle Orbiter

The flight problems experienced with the reusable Space Shuttle Orbiter have decreased during subsequent flights of each vehicle. By comparison to first flights of previous vehicles, the problems encountered on the initial flight of each new vehicle entering the fleet decreased. This improvement in turn has reduced the turnaround time between flights significantly and thus greatly enhanced the increased Space Shuttle launch frequency. The reusable manned space vehicle concept necessitated the development of a flight problem recognition and resolution system which would enable a thorough and timely vehicle turnaround flow. Flight evaluation, testing, and repair of manned spacecraft to enhance reliability and to ensure mission success is a unique activity. Real-time recognition of the flight problem, prompt isolation of the cause, and timely implementation of the corrective action are the keys to maintaining an operational fleet. Examples of flight problems that have been encountered as well as the corrective actions implemented during the first 24 Space Shuttle missions are presented. The corrective actions taken to preclude problem recurrence include modifications of hardware designs, manufacturing processes, flight software, test methods, and operational procedures.

Mechelay, Joseph E.↗

NASA NTRS1989

AH-1S communication switch integration program

The C-6533/ARC communication system as installed on the test AH-1E Cobra helicopter was modified to allow discrete radio selection of all aircraft radios at the cyclic radio/intercommunication system switch. The current Cobra-fleet use of the C-6533 system is cumbersome, particularly during low-altitude operations. Operationally, the current system C-6533 configuration and design requires the pilot to estimate when he can safely remove his hand from an active flight control to select radios during low-altitude flight. The pilot must then physically remove his hand from the flight control, look inside the cockpit to select and verify the radio selection and then effect the selected radio transmission by activating the radio/ICS switch on the cyclic. This condition is potentially hazardous, especially during low-level flight at night in degraded weather. To improve pilot performance, communications effectiveness, and safety, manprint principles were utilized in the selection of a design modification. The modified C-6533 design was kept as basic as possible for potential Cobra-fleet modification. The communications system was modified and the design was subsequently flight-tested by the U.S. Army Aeroflightdynamics Directorate and NASA at the NASA Ames Research Center, Mountain View, California. The design modification enables the Cobra pilot to maintain hands-on flight controls while selecting radios during nap-of-the-Earth (NOE) flight without looking inside the cockpit which resulted in reduced pilot workload ratings, better pilot handling quality ratings and increased flight safety for the NOE flight environment.

Haworth, Loran↗

NASA NTRS1989

Effects of lightning on operations of aerospace vehicles

Traditionally, aircraft lightning strikes were a major aviation safety issue. However, the increasing use of composite materials and the use of digital avionics for flight critical systems will require that more specific lightning protection measures be incorporated in the design of such aircraft in order to maintain the excellent lightning safety record presently enjoyed by transport aircraft. In addition, several recent lightning mishaps, most notably the loss of the Atlas/Centaur-67 vehicle at Cape Canaveral Air Force Station, Florida in March 1987, have shown the susceptibility of aircraft and launch vehicles to the phenomenon of vehicle-triggered lightning. The recent findings of the NASA Storm Hazards Program were reviewed as they pertain to the atmospheric conditions conducive to aircraft lightning strikes. These data are then compared to recent summaries of lightning strikes to operational aircraft fleets. Finally, the new launch commit criteria for triggered lightning being used by NASA and the U.S. Defense Department are summarized. The NASA Research data show that the greatest probability of a direct strike in a thunderstorm occurs at ambient temperatures of about -40 C. Relative precipitation and turbulence levels were characterized as negligible to light for these conditions. However, operational fleet data have shown that most aircraft lightning strikes in routine operations occur at temperatures near the freezing level in non-cumulonimbus clouds. The non-thunderstorm environment was not the subject of dedicated airborne lightning research.

Fisher, Bruce D.↗

NASA NTRS1989

United States space transportation survey

Different developmental paths for the U.S. space transportation fleet are discussed. Development of a purely cargo, unmanned space shuttle, using many components of the present manned space shuttle system, is presented. Future manned spacecraft solutions are discussed. Launch vehicle programs for unmanned missions are described. The Titan solid rocket motor upgrade is identified as the biggest improvement in this area. A return to a better balance between manned and unmanned launch systems for space transportation is predicted. The Titan, Delta, Scout, and Pegasus families of rockets are described. The need to upgrade this fleet in meeting the space challenges of the future is stressed.

Branscome, Darrel R.↗

NASA NTRS1990

High-speed civil transport study: Special factors

Studies relating to environmental factors associated with high speed civil transports were conducted. Projected total engine emissions for year 2015 fleets of several subsonic/supersonic transport fleet scenarios, discussion of sonic boom reduction methods, discussion of community noise level requirements, fuels considerations, and air traffic control impact are presented.

Source record↗

NASA NTRS1989

Nuclear-electric propulsion - Manned Mars propulsion options

Nuclear-electric propulsion can significantly reduce the launch mass for manned Mars missions. By using high-specific-impulse (lsp) electric propulsion systems with advanced nuclear reactors, the total mass-to-orbit for a series of manned Mars flight is reduced. Propulsion technologies required for the manned Mars mission are described. Multi-megawatt Ion and Magneto-Plasma-Dynamic (MPD) propulsion thrusters, Power-Processing Units and nuclear power source are needed. Xenon (Xe)-Ion and MPD thruster performance are detailed. Mission analyses for several Mars mission options are addressed. Both MPD and Ion propulsion were investigated. A four-megawatt propulsion system power level was assumed. Mass comparisons for all-chemical oxygen/hydrogen propulsion missions and combined chemical and nuclear-electric propulsion Mars fleets are included. With fleets of small nuclear-electric vehicles, short trip times to Mars are also enabled.

Palaszewski, Bryan↗

NASA NTRS1990

Procedure for generating global atmospheric engine emissions data from future supersonic transport aircraft. The 1990 high speed civil transport studies

The input for global atmospheric chemistry models was generated for baseline High Speed Civil Transport (HSCT) configurations at Mach 1.6, 2.2, and 3.2. The input is supplied in the form of number of molecules of specific exhaust constituents injected into the atmosphere per year by latitude and by altitude (for 2-D codes). Seven exhaust constituents are currently supplied: NO, NO2, CO, CO2, H2O, SO2, and THC (Trace Hydrocarbons). An eighth input is also supplied, NO(x), the sum of NO and NO2. The number of molecules of a given constituent emitted per year is a function of the total fuel burned by a supersonic fleet and the emission index (EI) of the aircraft engine for the constituent in question. The EIs for an engine are supplied directly by the engine manufacturers. The annual fuel burn of a supersonic fleet is calculated from aircraft performance and economic criteria, both of which are strongly dependent on basic design parameters such as speed and range. The altitude and latitude distribution of the emission is determined based on 10 Intern. Air Transport Assoc. (IATA) regions chosen to define the worldwide route structure for future HSCT operations and the mission flight profiles.

Sohn, R. A.↗

NASA NTRS1991

The atmospheric effects of stratospheric aircraft: A topical review

In the late 1960s the aircraft industry became interested in developing a fleet of supersonic transports (SSTs). Between 1972 and 1975, the Climatic Impact Assessment Program (CIAP) studied the possible environmental impact of SSTs. For environmental and economic reasons, the fleet of SSTs was not developed. The Upper Atmosphere Research Program (UARP) has recently undertaken the responsibility of directing scientific research needed to assess the atmospheric impact of supersonic transports. The UARP and the High-Speed Research Program asked Harold Johnston to review the current understanding of aircraft emissions and their effect on the stratosphere. Johnston and his colleagues have recently re-examined the SST problem using current models for stratospheric ozone chemistry. A unique view is given here of the current scientific issues and the lessons learned since the beginning of CIAP, and it links the current research program with the assessment process that began two years ago.

Johnston, Harold S.↗

NASA NTRS1991

The atmospheric effects of stratospheric aircraft: A current consensus

In the early 1970's, a fleet of supersonic aircraft flying in the lower stratosphere was proposed. A large fleet was never built for economic, political, and environmental reasons. Technological improvements may make it economically feasible to develop supersonic aircraft for current markets. Some key results of earlier scientific programs designed to assess the impact of aircraft emissions on stratospheric ozone are reviewed, and factors that must be considered to assess the environmental impact of aircraft exhaust are discussed. These include the amount of nitrogen oxides injected in the stratosphere, horizontal transport, and stratosphere/troposphere assessment models are presented. Areas in which improvements in scientific understanding and model representation must be made to reduce the uncertainty in model calculations are identified.

Douglass, A. R.↗

NASA NTRS1987

Feasibility of an onboard wake vortex avoidance system

It was determined that an onboard vortex wake detection system using existing, proven instrumentation is technically feasible. This system might be incorporated into existing onboard systems such as a wind shear detection system, and might provide the pilot with the location of a vortex wake, as well as an evasive maneuver so that the landing separations may be reduced. It is suggested that this system might be introduced into our nation's commuter aircraft fleet and major air carrier fleet and permit a reduction of current landing separation standards, thereby reducing takeoff and departure delays.

Bilanin, Alan J.↗

NASA NTRS1991

NASA/Ames Research Center's science and applications aircraft program

NASA-Ames Research Center operates a fleet of seven Science and Applications Aircraft, namely the C-141/Kuiper Airborne Observatory (KAO), DC-8, C-130, Lear Jet, and three ER-2s. These aircraft are used to satisfy two major objectives, each of equal importance. The first is to acquire remote and in-situ scientific data in astronomy, astrophysics, earth sciences, ocean processes, atmospheric physics, meteorology, materials processing and life sciences. The second major objective is to expedite the development of sensors and their attendant algorithms for ultimate use in space and to simulate from an aircraft, the data to be acquired from spaceborne sensors. NASA-Ames Science and Applications Aircraft are recognized as national and international facilities. They have performed and will continue to perform, operational missions from bases in the United States and worldwide. Historically, twice as many investigators have requested flight time than could be accommodated. This situation remains true today and is expected to increase in the years ahead. A major advantage of the existing fleet of aircraft is their ability to cover a large expanse of the earth's ecosystem from the surface to the lower stratosphere over large distances and time aloft. Their large payload capability allows a number of scientists to use multi-investigator sensor suites to permit simultaneous and complementary data gathering. In-flight changes to the sensors or data systems have greatly reduced the time required to optimize the development of new instruments. It is doubtful that spaceborne systems will ever totally replace the need for airborne science aircraft. The operations philosophy and capabilities exist at NASA-Ames Research Center.

Hall, G. Warren↗

NASA NTRS1992

Ozone Response to Aircraft Emissions: Sensitivity Studies with Two-dimensional Models

Our first intercomparison/assessment of the effects of a proposed high-speed civil transport (HSCT) fleet on the stratosphere is presented. These model calculations should be considered more as sensitivity studies, primarily designed to serve the following purposes: (1) to allow for intercomparison of model predictions; (2) to focus on the range of fleet operations and engine specifications giving minimal environmental impact; and (3) to provide the basis for future assessment studies. The basic scenarios were chosen to be as realistic as possible, using the information available on anticipated developments in technology. They are not to be interpreted as a commitment or goal for environmental acceptability.

Ko, Malcolm K. W.↗

NASA NTRS1990

A land mobile satellite data system

The Telesat Mobile Incorporated (TMI) Mobile Data System (MDS) was developed to apply satellite technology to the transportation industry's requirement for a fleet management system. It will provide two-way messaging and automatic position reporting capabilities between dispatch centers and customers' fleets of trucks. The design was based on the Inmarsat L-Band space segment with system link parameters and margins adjusted to meet the land mobile satellite channel characteristics. The system interfaces with the Teleglobe Des Laurentides earth station at Weir, Quebec. The signaling protocols were derived from the Inmarsat Standard C packet signalling system with unique trucking requirements incorporated where necessary.

Kent, John D. B.↗

NASA NTRS1992

Lidar Monitoring of Mexico City's Atmosphere During High Air Pollution Episodes

Over the last two decades, Mexico City, like many large industrial and populous urban areas, has developed a serious air pollution problem, especially during the winter months when there are frequent temperature inversions and weak winds. The deteriorating air quality is the result of several factors. The basin within which Mexico City lies in Mexico's center of political, administrative and economic activity, generating 34 percent of the gross domestic product and 42 percent of the industrial revenue, and supporting a population which is rapidly approaching the 20 million mark. The basin is surrounded by mountains on three sides which end up preventing rapid dispersal of pollutants. Emissions from the transportation fleet (more than 3 million vehicles) are one of the primary pollution sources, and most are uncontrolled. Catalytic converters are just now working their way into the fleet. The Mexico City Air Quality Research Initiative in an international collaboration project between the Los Alamos National Laboratory and the Mexican Petroleum Institute are dedicated to the investigation of the air quality problem in Mexico City. The main objective of the project is to identify and assess the cost and benefits of major options being proposed to improve the air quality. The project is organized into three main activity areas: (1) modeling and simulation; (2) characterization and measurements; and (3) strategic evaluation.

Quick, C. R., Jr.↗

NASA NTRS1991

Naval Space Surveillance Center uses of time, frequency, and phase

The Naval Space Surveillance Center (NAVSPASUR) is an operational naval command that has the mission of determining the location of all manmade objects in space and transmitting information on objects of interest to the fleet. NAVSPASUR operates a 217 MHz radar fence that has 9 transmitting and receiving stations deployed in a line across southern Continental United States (CONUS). This surveillance fence provides unalerted detection of satellites overflying CONUS. NAVSPASUR also maintains a space catalog of all orbiting space objects. NAVSPASUR plays an important role as operational alternate to the primary national Space Surveillance Center (SSC) and Space Defence Operations Center (SPADOC). In executing these responsibilities, NAVSPASUR needs precise and/or standardized time and frequency in a number of applications. These include maintenance of the radar fence references to specification, and coordination with other commands and agencies for data receipt and dissemination. Precise time and frequency must be maintained within each site to enable proper operation of the interferometry phasing technique used. Precise time-of-day clocking must exist between sites for proper intersite coordination. After 'time tags' are attached to the data at the receiver sites, proper referencing and standardization are necessary at the Dahlgren, Va. operations center to ensure proper data synchronization and communications with the fleet and other agencies.

Carroll C. Hayden↗